The three DeAutremont brothers destroyed a mail car and killed four men, including a Railway Post Office clerk, when they tried to rob a Southern Pacific train on October 11, 1923. After botching the robbery, the three fled the scene of the crime in a panic, leaving some items, including a pair of overalls, behind. The items left behind helped authorities learn the identities of the murderers.

Postal inspectors asked chemist Edward Heinrich to inspect the clues left behind by the robbers to see if he could tell them anything about the fugitives. Given a pair of overalls found at the crime scene, Heinrich developed a profile of a likely suspect.